The 34-year-old took over as Firhill first choice midway through the campaign when his Jags counterpart got injured and never looked back as he helped Alan Archibald's side retain their place in the Premiership.
Fox's return to the first team only lasted a few minutes on the final day of the campaign as he was stretched off with ankle damage following a collision with Ross County's Jordan Slew.
He was back between the sticks on Saturday as Thistle rounded off their Spanish pre-season tour with a 4-0 loss to English Championship side Brighton, with trialist trio Carl Magnay, Darren Barr and Jordan Mustoe all given another chance to impress boss Archibald.
The defeat to Albion came just days after Gallacher got his first minutes of action in the 3-1 victory over FC Pinatar on Wednesday night and the Jags' goalie guru is preparing for a tough battle to hold off his glove rival and protege this term.
He said: "It was a scare for us all when Foxy got injured. It was bizarre how it happened and he looked in a lot of pain.
"We were fearful that it could have been serious and a really bad one. But he has come through his rehab and we are just counting our blessings that it wasn't worse.
"That No.1 jersey is up for grabs, like every position. There is nobody guaranteed a game.
"We have all got to work hard in pre-season and the games and show the gaffer what we are capable of.
"He will pick the team he feels is the strongest to win when the campaign gets under way as we look to get off to a great start."